Core recovery recorder



CORE RECOVERY RECORDER Filed Oct. 25, 1947 FTC-Z 1 Patented Jan. 9, 1951CORE RECOVERY RECORDER Benjamin W. Sewell, Tulsa, lrla., assignor toStandard Oil Development Company, a corporation of Delaware ApplicationOctober 25, 1947, Serial No. 782,097

2 Claims. (Cl. 348-127) The present invention is directed to anapparatus for use in the drilling and collection of cores of asubterranean formation.

In the drilling of earth bore holes, particularly those drilled for oil,it is common practice to secure cores of a subterranean formation to bestud ed. These are commonly secured by using what is known as' a corebit, which is similar to the ordinary bit except that it has a largecentral opening through which a core can pass upwardly into a collectionchamber. Various types of core barrels have been devised for use in thisoperation. A conventional type s known as the wire line type. This typeof barrel is lowered on a wire line into a drill stem to a seat Justabove the drill bit. As the core is cut it passes up into the barrel andis collected and eventually brought to the surface at the end of a wireline. Other particular types of core barrels which have been developedare those known as pressure core barrels which secure a core of asubterranean formation under the pressure existing in the formation, andbring the core to the surface without loss of that pressure.

In all coring operations difllculty is encountered by reason of the factthat the operator is so far from the scene of the actual coring. Hebrings his core barrel to the surface and finds in it a certa n amountof core but he has no assurance at all as to the part of the formation.considered vertically, represented by that portion of core. In otherwords, he may drill a twenty foot core out of a formation and bring tothe surface only a few feet. He would usually assume that he has lostthe bottom 18 feet of core and that the sample he recovered representedthe top two feet. It is quite possible, however, that the first severaltop feet of the core may not be recovered by reason of the fact that itcrumbles and is washed away. Therefore, if he has recovered only a fewfeet out of 20 feet, he does not know whether it is the top 2 feet, thebottom 2 feet, or something in between.

The principal object of the present invention is toprovide a device foruse in conjunction with coring operations to supply information as tothe course of the coring operation.

A more specific object of the present invention is to provide a deviceof the character described in which there is made a continuous record ofthe rate at which core enters a core barrel and of the height it reachesin the core barrel.

Other objects and advantages of the present invention will appear fromthe following detailed description of the accompanying drawing in which:

Fig. 1 is a vertical section through a core barrel containing the deviceof the present invention; and

Fig. 2 is a plan view of the device.

Referring to the drawing in detail, numeral l designates the wall of acore barrel. Ordinarily a core barrel is provided at its lower end witha plug which is attached to the wall by shear pins. This plug serves tokeep out foreign matter from the core barrel until the actual coringoperation begins. 'As the core is cut and starts to move upwardly itshears off the pins holding the plug, and pushes the plug back up intothe core barrel so that room is made therein for the core. The device ofthe present invention can serve the purpose of the ordinary plug. Thus,the device of the present invention is a cylindrical casing 2 and isprovided at its lower end with a shear ring 3 which is connected byshear pins to the lower end of the core barrel.

The cylindrical body has a central chamber 4, in the lower end of whichis arranged a spring motor or other type of motor ll having a shaft 6journaled in the partition I and connected above the partition with oneend of a drum 8 which rotates with the shaft and has fixed to its innerwall a chart in the manner usual with recording devices of this type.

Fixed to the upper wall of the chamber 4 is a post 9 which carries atits lower end a plate In in which is Journaled a threaded rod 1 I whichextends upwardly through the upper wall of the chamber 4 into a slot l2at the upper end of the cylindrical member 2. The upper end of themember H has secured thereto a worm l3 which is in engagement with agear H carried by a shaft I 5, to which is also pinned a large wheel l6having a knurled surface. This wheel is of sufficient diameter to pressagainst the wall of the core barrel under the influence of spacingspring members [1 suitably disposed about the periphery of thecylindrical member 2.

In threaded engagem nt with the lower end of the member II is a followeri8 carrying at its end a stylus l9 which operates on the paper chart onthe inner wall of the drum 8. This follower is also slidably mounted onthe post 9 wh reby rotation of the element ll causes the follower tomove up and down vertically.

Below the cylindrical chamber 4 the cylinder 2 has a second slot 20 inwhich is journaled a wheel 2| corresponding to the wheel I6. This wheelis present only to balance the device.

When a coring operation is to be performed the device described is fixedin the core barrel in the position ordinarily occupied by the plug.

, 3 I The clockwork drive is started in operation. As the core entersthe chamber it pushes the device upwardly. As the device moves upwardlythe knurled wheel I6 is caused to rotate and this in turn rotates theelement l I, causing the stylus to move upwardly n the chart. If, duringthe coring operation some of the core is lost as by being crumbled andwashed away, it does not cause the stylus to move up. Again, after thecoring operation is completed and the core assembly is brought to thesurface, it there is any core lost from the barrel which would result inthe recording device moving downwardly the chart will give an indicationof this occurrence. The distance to which the stylus rises on the chartindicates the amount of core which enters the barrel and the slope ofthe trace on the chart gives an indication of the rate at which the coreentered the barrel. I

At the same time the driller records at the surface the drilling rate,or the rate at which the bit moves in to the formation. By comparing thedriling rate log with-the core movement log, the operator canreconstruct what happened during the coring operation. For example, ifthe drilling rate log shows a penetration of one foot per minute at thebeginning of the coring operation and no core movement into the corebarrel is recorded during this period, the operator knows that the topportion of the core was lost.

The nature and objects of the present invention having been describedand illustrated, what is claimed as new and useful and is desired to besecured by Letters Patent is:

1. A core device comprising a core barrel, a

sealed cylindrical chamber slidingly mounted in said barrel and normallyresting on the bottom thereof, a cylindrical chart-holding means mountedfor rotation in said chamber and carrying a chart on its inner surface,means for rotating saidchart-holding means at predetermined rate, athreaded rod rotatably mounted in a vertical position within saidchamber, a, follower threadedly engaged with said threaded rod, a

stylus mounted on said follower and adapted to contact said chart, awheel carried by said cylindrical chamber in a position engaging saidwheel with the inside wall of said core barrel so as to rotate saidwheel when said chamber is caused to slide lengthwise of said barrel,means for transferring motion of said wheel to said threaded rod andspring means afiixed to said chamber urging saidwheel into contact withthe wall of said core barrel.

2. A recording device for recording the rate of recovery of a core in acor barrel which comprises a cylindrical casing adapted to fit slidablywithin a core barrel, a cylindrical chart-holding means mountedforrotation in said casing and carrying a chart on its inner surface, meansfor rotating said chart-holding means at a predetermined rate, athreaded rod rotatably mounted in a vertical position within saidcasing, a follower threadedly engaged with said threaded rod, a stylusmounted on said follower and adapted to contact said chart, a wheelcarried by said casing in a position adapted to engage the wheel withthe inside wall of a core barrel so as to rotate said wheel when saidcasing is caused to slide lengthwise of said core barrel, means fortransferring motion of said wheel to said threaded rod and spring meansamxed to saidcasng and adapted to urge said wheel into contact with theinside wall of a core barrel.

BENJAMIN W. SEWELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 713,784 Meller Nov, 18, 19021,815,672 Jones July 21, 1931 1,894,996 Macready Jan. 24, 1933 1,901,567Rogatz Mar. 14, 1933 1,955,855 Marx Apr. 24, 1934 2,200,885 Johnson May14, 1940

